Class: RuboCop::Cop::Style::ZeroLengthPredicate
Relationships & Source Files | |
Super Chains via Extension / Inclusion / Inheritance | |
Class Chain:
self,
::RuboCop::Cop::AutoCorrector ,
::RuboCop::Cop::Base ,
::RuboCop::ExcludeLimit ,
NodePattern::Macros,
RuboCop::AST::Sexp
|
|
Instance Chain:
self,
::RuboCop::Cop::Base ,
::RuboCop::Cop::AutocorrectLogic ,
::RuboCop::Cop::IgnoredNode ,
::RuboCop::Util ,
RuboCop::AST::Sexp
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|
Inherits: |
RuboCop::Cop::Base
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Defined in: | lib/rubocop/cop/style/zero_length_predicate.rb |
Overview
Checks for numeric comparisons that can be replaced
by a predicate method, such as receiver.length == 0
,
receiver.length > 0
, and receiver.length != 0
,
receiver.length < 1
and receiver.size == 0
that can be
replaced by receiver.empty?
and !receiver.empty?
.
Note
|
File , Tempfile , and StringIO do not have empty?
so allow size == 0 and size.zero? .
|
Constant Summary
-
NONZERO_MSG =
# File 'lib/rubocop/cop/style/zero_length_predicate.rb', line 41'Use `!empty?` instead of `%<current>s`.'
-
RESTRICT_ON_SEND =
# File 'lib/rubocop/cop/style/zero_length_predicate.rb', line 43%i[size length].freeze
-
ZERO_MSG =
# File 'lib/rubocop/cop/style/zero_length_predicate.rb', line 40'Use `empty?` instead of `%<current>s`.'
::RuboCop::Cop::Base
- Inherited
Class Attribute Summary
::RuboCop::Cop::AutoCorrector
- Extended
::RuboCop::Cop::Base
- Inherited
.gem_requirements, .lint?, | |
.support_autocorrect? | Returns if class supports autocorrect. |
.support_multiple_source? | Override if your cop should be called repeatedly for multiple investigations Between calls to |
Class Method Summary
::RuboCop::Cop::Base
- Inherited
.autocorrect_incompatible_with | List of cops that should not try to autocorrect at the same time as this cop. |
.badge | Naming. |
.callbacks_needed, .cop_name, .department, | |
.documentation_url | Returns a url to view this cops documentation online. |
.exclude_from_registry | Call for abstract Cop classes. |
.inherited, | |
.joining_forces | Override and return the Force class(es) you need to join. |
.match? | Returns true if the cop name or the cop namespace matches any of the given names. |
.new, | |
.requires_gem | Register a version requirement for the given gem name. |
.restrict_on_send |
::RuboCop::ExcludeLimit
- Extended
exclude_limit | Sets up a configuration option to have an exclude limit tracked. |
transform |
Instance Attribute Summary
::RuboCop::Cop::Base
- Inherited
::RuboCop::Cop::AutocorrectLogic
- Included
Instance Method Summary
- #on_csend(node)
- #on_send(node)
- #check_nonzero_length_comparison(node) private
- #check_zero_length_comparison(node) private
- #check_zero_length_predicate(node) private
-
#non_polymorphic_collection?(node)
private
Some collection like objects in the Ruby standard library implement
#size
, but not#empty
. - #nonzero_length_comparison(node) private
- #other_length_node(node) private
- #replacement(node) private
- #zero_length_comparison(node) private
- #zero_length_node(node) private
- #zero_length_predicate?(node) private
::RuboCop::Cop::Base
- Inherited
#add_global_offense | Adds an offense that has no particular location. |
#add_offense | Adds an offense on the specified range (or node with an expression) Unless that offense is disabled for this range, a corrector will be yielded to provide the cop the opportunity to autocorrect the offense. |
#begin_investigation | Called before any investigation. |
#callbacks_needed, | |
#cop_config | Configuration Helpers. |
#cop_name, #excluded_file?, | |
#external_dependency_checksum | This method should be overridden when a cop’s behavior depends on state that lives outside of these locations: |
#inspect, | |
#message | Gets called if no message is specified when calling |
#name | Alias for Base#cop_name. |
#offenses, | |
#on_investigation_end | Called after all on_… |
#on_new_investigation | Called before all on_… |
#on_other_file | Called instead of all on_… |
#parse | There should be very limited reasons for a Cop to do it’s own parsing. |
#parser_engine, | |
#ready | Called between investigations. |
#relevant_file?, #target_rails_version, #target_ruby_version, #annotate, #apply_correction, #attempt_correction, | |
#callback_argument | Reserved for Cop::Cop. |
#complete_investigation | Called to complete an investigation. |
#correct, #current_corrector, | |
#current_offense_locations | Reserved for Commissioner: |
#current_offenses, #currently_disabled_lines, #custom_severity, #default_severity, #disable_uncorrectable, #enabled_line?, #file_name_matches_any?, #find_message, #find_severity, #range_for_original, #range_from_node_or_range, | |
#reset_investigation | Actually private methods. |
#use_corrector |
::RuboCop::Cop::AutocorrectLogic
- Included
#disable_offense, #disable_offense_at_end_of_line, #disable_offense_before_and_after, #disable_offense_with_eol_or_surround_comment, #heredoc_range, #max_line_length, #multiline_ranges, #multiline_string?, | |
#range_by_lines | Expand the given range to include all of any lines it covers. |
#range_of_first_line, #range_overlaps_offense?, #string_continuation?, #surrounding_heredoc?, #surrounding_percent_array? |
::RuboCop::Cop::IgnoredNode
- Included
Constructor Details
This class inherits a constructor from RuboCop::Cop::Base
Instance Method Details
#check_nonzero_length_comparison(node) (private)
[ GitHub ]# File 'lib/rubocop/cop/style/zero_length_predicate.rb', line 85
def check_nonzero_length_comparison(node) nonzero_length_comparison = nonzero_length_comparison(node.parent) return unless nonzero_length_comparison lhs, opr, rhs = nonzero_length_comparison return if non_polymorphic_collection?(node.parent) add_offense( node.parent, message: format(NONZERO_MSG, current: "#{lhs} #{opr} #{rhs}") ) do |corrector| corrector.replace(node.parent, replacement(node.parent)) end end
#check_zero_length_comparison(node) (private)
[ GitHub ]# File 'lib/rubocop/cop/style/zero_length_predicate.rb', line 70
def check_zero_length_comparison(node) zero_length_comparison = zero_length_comparison(node.parent) return unless zero_length_comparison lhs, opr, rhs = zero_length_comparison return if non_polymorphic_collection?(node.parent) add_offense( node.parent, message: format(ZERO_MSG, current: "#{lhs} #{opr} #{rhs}") ) do |corrector| corrector.replace(node.parent, replacement(node.parent)) end end
#check_zero_length_predicate(node) (private)
[ GitHub ]# File 'lib/rubocop/cop/style/zero_length_predicate.rb', line 58
def check_zero_length_predicate(node) return unless zero_length_predicate?(node.parent) return if non_polymorphic_collection?(node.parent) offense = node.loc.selector.join(node.parent.source_range.end) = format(ZERO_MSG, current: offense.source) add_offense(offense, message: ) do |corrector| corrector.replace(offense, 'empty?') end end
#non_polymorphic_collection?(node) (private)
Some collection like objects in the Ruby standard library
implement #size
, but not #empty
. We ignore those to
reduce false positives.
# File 'lib/rubocop/cop/style/zero_length_predicate.rb', line 147
def_node_matcher :non_polymorphic_collection?, <<~PATTERN {(send (send (send (const {nil? cbase} :File) :stat _) ...) ...) (send (send (send (const {nil? cbase} {:File :Tempfile :StringIO}) {:new :open} ...) ...) ...)} PATTERN
#nonzero_length_comparison(node) (private)
[ GitHub ]# File 'lib/rubocop/cop/style/zero_length_predicate.rb', line 114
def_node_matcher :nonzero_length_comparison, <<~PATTERN {(call (call (...) ${:length :size}) ${:> :!=} (int $0)) (call (int $0) ${:< :!=} (call (...) ${:length :size}))} PATTERN
#on_csend(node)
[ GitHub ]# File 'lib/rubocop/cop/style/zero_length_predicate.rb', line 51
def on_csend(node) check_zero_length_predicate(node) check_zero_length_comparison(node) end
#on_send(node)
[ GitHub ]# File 'lib/rubocop/cop/style/zero_length_predicate.rb', line 45
def on_send(node) check_zero_length_predicate(node) check_zero_length_comparison(node) check_nonzero_length_comparison(node) end
#other_length_node(node) (private)
[ GitHub ]# File 'lib/rubocop/cop/style/zero_length_predicate.rb', line 138
def_node_matcher :other_length_node, <<~PATTERN {(call $(call _ _) _ _) (call _ _ $(call _ _))} PATTERN
#replacement(node) (private)
[ GitHub ]# File 'lib/rubocop/cop/style/zero_length_predicate.rb', line 119
def replacement(node) length_node = zero_length_node(node) if length_node&.receiver return "#{length_node.receiver.source}#{length_node.loc.dot.source}empty?" end other_length_node = other_length_node(node) "!#{other_length_node.receiver.source}#{other_length_node.loc.dot.source}empty?" end
#zero_length_comparison(node) (private)
[ GitHub ]# File 'lib/rubocop/cop/style/zero_length_predicate.rb', line 106
def_node_matcher :zero_length_comparison, <<~PATTERN {(call (call (...) ${:length :size}) $:== (int $0)) (call (int $0) $:== (call (...) ${:length :size})) (call (call (...) ${:length :size}) $:< (int $1)) (call (int $1) $:> (call (...) ${:length :size}))} PATTERN
#zero_length_node(node) (private)
[ GitHub ]# File 'lib/rubocop/cop/style/zero_length_predicate.rb', line 130
def_node_matcher :zero_length_node, <<~PATTERN {(send $(call _ _) :== (int 0)) (send (int 0) :== $(call _ _)) (send $(call _ _) :< (int 1)) (send (int 1) :> $(call _ _))} PATTERN
#zero_length_predicate?(node) (private)
[ GitHub ]# File 'lib/rubocop/cop/style/zero_length_predicate.rb', line 101
def_node_matcher :zero_length_predicate?, <<~PATTERN (call (call (...) {:length :size}) :zero?) PATTERN